Statistics Quick Reference Sheet
Test Formula Purpose/Notes
× = Σ of data / N
Mean The average of the data.
Add all of your data points together, and then
divide by the number of data points.
1. Place numbers in order
Median 2. Find the number in the middle The middle number when the data is in order.
3. If even amt of numbers, average the
two in the middle
Mode Find the data point that occurs most Most frequently occurring number.
frequently. Can be more than one data point orno data points.
Range = (Highest Score – Lowest Score) Describes how spread out the data set is.
( ) Describes the scatter of the scores around the mean.
Standard Deviation √
1. Put data in rank order from “worsDescribes the relative position of a data point in more detail than the
Percentile “best” – number the ranks median.
2. % = rank of data poinOR/ (%*N =
rank of data point)
If larger numbers are better: Express how far away a number is from the mean, in terms of
If smaller numbers are better: standard deviatio